Watch calendar drive mechanism



D. J. ROGERS Feb. 6, 1968 WATCH CALENDAR DRIVE MECHANISM Filed March 11, 1966 S on E G 0 R 0 J F. D W L A N 0 D ATTORNEYS 3,367,104 WATCH CALENDAR DRIVE MECHANISM Donald J. Rogers, Lancaster, Pa., assignor to Hamilton Watch Company, Lancaster, Pa., a corporation of Pennsylvania Filed Mar. 11, 1966, Ser. No. 533,512 Claims. (CI. 5858) This invention relates to a novel drive arrangement for the date indicating or calendar devices of a timepiece and more particularly to an improved calendar drive and detent mechanism particularly suited for low power time pieces, such as electrical watches.

The device of the present invention relates to a mechanical calendar mechanism designed for use with low torque output electric watches as well as mechanical or electrical watches, clocks and other timing devices where automatic date readout is desired. This system is believed to be unique in that it combines all desirable calendar features in one mechanism which does not require excessive energy as do other calendar mechanisms previously proposed. These desirable features include instantaneous date change, accuracy, and repeatability in date change, accurate date positioning, calendar ring detenting (holding and releasing), and rapid manual calendar ring setting, all features being combined in a simple mechanism requiring little space and energy. Previous devices having most of these features also have energy requirements excessive of electric watch capabilities and other previous mechanisms which do have low enough energy requirements fail seriously in one or more of the above desirable features.

There are many existing timepiece calendar systems in which the movement of a watch or like timepiece is provided with a date bearing indicia carrier which is operated in timed relation to the hour wheel of the timepiece so as to indicate successive dates. Many of the existing calendar clock systems are simply too bulky for small watch movements and cannot stand the reduction in size necessary for incorporation in a commercial watch. In typical existing calendar watch systems, the dial side of the movement is provided with a calendar ring or disc that is rotatably mounted below the dial and bears 31 equally spaced numbers, which are successively exposed through a window in the dial as the disc is advanced 1 of a revolution each twenty-four hours by a drive system interconnecting the calendar ring with the dial train of the watch.

In existing calendar watch systems, the dial train is effectively disconnected from the calendar indicia ring or disc for twenty-one hours, with the appropriate date number of the calendar ring being exposed through a window in the watch dial to indicate the date. In the remaining approximately three hour period, the dial train is drivingly engaged with the calendar ring, usually by a camming arrangement, so as to cause the calendar ring to advance & of a revolution. The dial ring is thus progressively moved in the remaining three hour period (which is usually around midnight) until the next date number is beneath the aforementioned dial window. That date number is exposed for the next twenty-one hours and is thereafter replaced by the next successive numbr when the calendar ring is again drivingly engaged with the dial train by the intermediate camming arrangement and thus displaced. Such existing calendar watch systems impose a quite high load on the source of power driving the dial train, and this load is more than existing electrical watch systems can bear with a compact long-lived power source. Also, due to the relatively high power requirements of such prior watch calendar systems, they are a problem with so called automatic or self-winding spring driven watches, when they are not in a full wind state.

Such prior calendar watch systems have other disadvantages. For example, the date ring can be turned in only one direction by manual operation of the usual crown and stem provided for setting the watch, whereby prolonged operation of the stem is necessary to turn the calendar dial to expose a lower date number through the dial window.

It is a principal object of the present invention to provide a new, improved calendar watch system which avoids the above-discussed and other shortcomings of prior calendar watch systems, and can therefore be used in small battery powered electric watches, or other types of watches which have insufficient power for the load imposed by the watch calendar systems heretofore commercially available.

Another object of the present invention is to provide a novel intermittent drive for a watch calendar mechanism wherein the calendar ring or other indicia bearing member is substantially instantaneously advanced one date position at or very near the exact stroke of midnight of each day.

Another object of the present invention is to provide a novel drive arrange-ment wherein the calendar ring of a watch mechanism is advanced through the release of a light spring continuously wound from the dial train during substantially the entire twenty-four hour period between date changes.

Another object of the present invention is to provide a novel combination calendar ring drive and detenting mechanism which only lightly loads the dial train.

Another object of the present invention is to provide a calendar drive mechanism having a simplified and reliable arrangement permitting easy and reliable manual setting of the calendar ring in either direction.

In the present invention, the calendar ring is provided with internal gear teeth adapted to be engaged with the pin of a Geneva pinion. During the entire period between substantially instantaneous date changes, the Geneva pinion is locked against movement. However, the pinion is coupled to a light spiral spring or hairspring which is continuously wound during this period so as to store energy for advancing the calendar ring substantially instantaneously upon release of the Geneva pinion. During the time that the spring is being wound, between date changes, apparatus cooperating with the Geneva pinion acts to automatically detent the calendar ring so as to maintain it in the proper position with the appropriate date exposed through a window in the watch dial. Movement of the Geneva pinion during the date change-over is accompanied by an automatic release of the detent mechanism so that the calendar ring is advanced by the previously wound spring free of any detent retarding forces as customarily experienced by previous constructions. Since the calendar ring is advanced free of any detent retardation, a very light spring may be used to advance the calendar ring and the relatively light nature of this spring imposes a corresponding light load on the dial train during the time that the spring is being wound.

A further important feature of the present invention resides in a novel pivotal mounting for the calendar ring advancing and detenting mechanism making it possible to readily adjust the calendar ring by manual manipulation of a setting stem in either direction.

These and further objects and advantages of the invention will be more apparent upon reference to the following specificatiomclaims and appended drawings, wherein:

FIGURE 1A shows the dial face of an electric watch incorporating the new improved calendar system of the present invention as it appears at 11:55 pm. on the 30th day of the month.

FIGURE 1B shows the dial face of the same watch as it appears at 12:01 am. on the 31st day of the month.

FIGURE 2 is an enlarged fragmentary plan view of 'a part of the dial side of the watch of FIGURES 1A and 1B showing operating elements of the calendar system; and

FIGURE 3 is a partial vertical section through a watch incorporating the calendar system of this invention.

Referring to the drawings, the numeral generally indicates a watch which may be any presently commercial- 1y available watch having a movement of suitable design.

.For example, the movement may be that used in the model 505 electric watch of the Hamilton Watch Company, Lancaster, Pa. disclosed in a Hamilton service bulletin #220, but modified to incorporate the Watch calendar system of this invention as hereinafter amplified. A1- ternatively, the watch 10 may be of the more recent type identified as Hamilton Model 510 Electric Watch.

The watch movement generally includes a pillar plate which is provided on its dial side with an annular peripheral ring having an internal shoulder for seating the lower exterior portion of an annular geared calendar ring, a portion of such ring being illustrated at 12 in FIGURE 2. A dial train bridge is concentrically mounted on the dial side of the pillar plate and the circular edge portions of the dial train bridge and the annular shoulder on the periphery of the pillar plate provide a track for the geared calendar ring 12 whereby calendar ring 12 is rotatable about central axis 14 of an hour wheel 16. For

a more detailed discussion of the mounting for the rotatable calendar ring 12, reference may be had to assignees copending application Serial No. 227,160, filed Oct. 1, 1962, now Patent No. 3,240,006, issued Mar. 15, 1966, which is incorporated herein by reference.

Rotatable about the central axis 14 of the watch in a conventional manner are hour hand 18 and minute hand 20, which pass over suitable hour indicia 22 on the dial 24 of the watch. Provided in the dial is an arcuate Window 26 through which is visibly displayed one of the indicia 28 on the upper surface 30 of the annular calendar ring 12. As illustrated in FIGURE 1A, the indicia 30 is visible through the window 26 up until substantially midnight of the 30th of the month. At this time, the calendar ring 12 is stepped of a revolution by the mechanism of this invention, such that shortly after midnight, as illustrated in FIGURE 1B, the calendar ring has ad vanced so that the numeral 31 is visible through dial window 26 indicating the new date as the 31st of the month.

Referring to FIGURE 2, the hour wheel 16 rotatable about central axis 14 drives a first gear wheel 32 mounted to rotate about axis 34. Carried for rotation with gear 32 about axis 34 is a first pinion 36, having teeth which mesh with the teeth of a second wheel 38, rotatable about axis 40. Rotatable with wheel 38 about axis 40 is a second pinion 42 having teeth meshing with the teeth of a drive pinion 44 rotatable about axis 46.

Referring now to both FIGURES 2 and 3, drive pinion 44 carries teeth which mesh with similar teeth 48 on a drive wheel 50. Wheel 50 is mounted to rotate about a shaft 52 whose lower end is stationarily secured in a bridge 54. This bridge is pivoted at one end to the watch movement 56 by a screw 58, threaded into a suitable aperture 60 in a stationary portion of the Watch movement. That is, the bridge 54 supports shaft 52 at one end and is pivoted adjacent its other end so as to be movable about the central longitudinal axis of the screw 58.

A Geneva pinion 62 is also rotatably mounted on shaft 52. This Geneva pinion carries a pin 64 adjacent its upper end and a release finger 66 adjacent its lower end. The extreme bottom of Geneva pinion 62 is secured to the inner coil of a light spring or hairspring 68. The outer coil of the spiral spring 68 is fixed or secured to the drive wheel 50. Both the Geneva pinion and drive wheel are rotatably or pivotally mounted on stationary shaft 52 by suitable bearings such as those indicated at '70 and 72.

Formed integrally with the Geneva pinion 6-2 at its upper end in FIGURE 3 is a circular segment 74. This circular segment cooperates with a plurality of equally spaced teeth 76 formed on the inner surface of the calendar ring 12 to index the ring. That is, the teeth are uniformly spaced to define separating slots or grooves 78 and the teeth themselves are provided with concave surfaces 80 having approximately the same curvature as the circular segment 74 of the Geneva pinion 62. The slots 78 are adapted to receive in succession the pin 64 carried by the Geneva pinion. When pin 64 is in mesh with a tooth opening 78, calendar ring 12 is rotated X revolution, thereby advancing the date by one day.

Also driven from the dial train of the watch and more specifically from the hour wheel 16 by way of second gear wheel 38 is a release pinion 82 rotatably mounted on shaft 84 for rotation about axis 86. Rotatable with release pinion 82 is a second Geneva pinion 88 which carries a release pin 90. Thus, Geneva pinion 88 is driven in synchronism with drive wheel 50 and in turn drives a Geneva wheel 92 having a plurality of slots 94, preferably four in number equally spaced around the circumference of the Geneva wheel, and adapted to receive in driving engagement the pin 90 on Geneva pinion 88. Geneva wheel 92 is rotatably mounted on a shaft 96 for rotation about an axis 98. Rotatable with the Geneva wheel 92 is a control disc 100 having a cut out portion 102 and an otherwise circular outer edge. As illustrated in FIG- URES 2 and 3, the outer edge of this control disc is normally in engagement with the release finger 66 carried by the first Geneva pinion 62. Finally, the bridge 54 upon which a portion of the drive assembly including wheel 50 and first Geneva pinion 62 are mounted is resiliently biased into a detent position with the surface of the circular segment 74 in close engagement with the concave surface 80 on one of the teeth 76 by a suitable detent spring such as the spring 106 illustrated in FIGURE 2.

In operation, wheel 50 is driven continuously at one revolution per 24 hours from the hour wheel 16 of the dial train. However, control disc 100 in engagement with release finger 66 prevent Geneva pinion 62 from rotating by restraining rotation of the release gear. As a result, spring 68 becomes wound, thereby storing energy for later indexing of the calendar ring 12. At the proper time for date change, i.e. at or around midnight, pin 90 of the second Geneva pinion 88 which is also continuously rotated in synchronism with the remainder of the drive assumes a position directly between the center of Geneva pinion 88 and the center of Geneva wheel 92. When the pin assumes a position directly beneath the centers of these two rotary elements, the pin is at a point where it imparts maximum rotational speed to the control disc 100 and this latter disc through its cut out segment portion 102 accurately releases finger 66 at repeatable twenty-four hours intervals. This release of the finger 66 by the out out 102 allows spring 68 to rapidly unwind and drive Geneva pinion 62 in rotation about the shaft 52. Rotation of Geneva pinion 62 causes pin 64 to mesh with one of the tooth slots 78 of the calendar ring 12 so as to index the calendar ring one date.

' During the rotation of the Geneva pinion 62, circular segment 74 provides the calendar. ring detenting function by holding and releasing the calendar ring automatically at the proper time. That is, the circular segment engages the concave surface 80 of one of the teeth until such time as pin 64 drivingly engages the same tooth. At this time, the rotating segment 74 moves clear of the concave surface of the tooth permitting the pin 64 to drive the calendar ring 12 of a revolution. However, as the pin in further rotation of pinion 62 begins to release from the slot 78, segment 74 again moves into engagement with the concave surface 80 of the next tooth, so as to hold and lock the calendar ring in the properly advanced position. After indexing, the Geneva pinion 62 is returned to its initial starting position by spring 68 and control disc 90 again blocks release finger 66 before it can begin a second rotation. The continuous rotation of wheel 50 during the next 24 hour period again winds spring 68 which stores energy for the next date change.

To provide for manual calendar ring indexing in either direction, the Geneva pinion 62 is mounted on the bridge 54 which is in turn pivoted at screw 58. This allows close fitting between the circular segment 74 with a concave surface of one of the teeth, but also permits the circular segment to disengage and provide a detenting action, when calendar ring 12 is forceably or manually rotated through the Watch setting mechanism in the conventional manner. During this disengagement during manual setting, the placement of drive wheel 50 and its driving pinion 44 is such that they remain in engagement thereby maintaining synchronism with the indicating hands 18 and 20 of the watch.

It is apparent from the above that the present invention provides a novel apparatus for indexing the calendar ring of a watch mechanism which apparatus places a minimum load on the dial train and hence the power source such as a small compact battery used to drive the watch. In previous arrangements involving the winding of a spring, the spring is of necessity of rather strong construction, since during the advancement step, the spring must not only drive the calendar ring against normal friction forces, but is also required to overcome the retarding force of separate spring biased detents or jumper mechanisms. Furthermore, this heavy spring in prior constructions has not been wound throughout the entire twenty-four hour period as in the present invention. Thus, the prior constructions have not evidenced the low load properties of the instant construction. Similarly, while efforts have been made in the past to eliminate the action of retarding detents or jumpers during calendar ring advancement, these mechanisms have suffered from other serious disadvantages including the lack of a substantially instantaneous change of date or the integral and automatic detenting feature provided by the circular segment 74 of the present invention in engagement with the concave surfaces of one of the teeth on the calendar ring.

Thus, the mechanism of the present invention overcomes one or more of the previously mentioned difficulties evidenced by prior disclosures in that it (1) continuously removes relatively small amounts of energy from the dial train of a watch movement and stores this energy in a spring for instantaneous release at the proper indexing time; (2) provides a Geneva member which can accurately release this energy for date or calendar ring indexing despite its relatively long cycle period; (3) provides a second Geneva member which (a) utilizes the spring potential energy for instantaneous date ring indexing (b) maintains the ring position in proper relationship to the date wndow and (c) provides the date ring detenting (holding and releasing) function automatically; (4) and provides an arrangement for pivotally mounting the second Geneva member which makes possible (a) an arrangement for unlocking the 6 date ring for manual setting (b) a ratcheting action for proper date ring positioning during manual setting and (c) manual setting which does not necessitate changing the time indicated by the watch hands and which does not interfere with the synchronization of the date change time.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. A calendar mechanism for timepieces comprising date indicating means, a spring, means coupled to one end of said spring for continuously winding said spring from the power train of said timepiece, indexing means coupled to the other end of said spring and normally spaced from said date indicating means for periodically indexing said date indicating means to the next date, means normally locking said indexing means against movement whereby energy is stored in said spring, and means operated in synchronism with said power train for periodically releasing said indexing means whereby said spring acts through said indexing means to advance said date indicating means to the next date.

2. A calendar mechansm for a timepiece comprising date indicating means, a spring, means for continuously winding said spring from the power train of said timepiece, means drivingly coupling said spring to said date indicating means, means operated in synchronism with said power train for periodically releasing said spring whereby said spring advances said date indicating means to the next date, a movable detent engaging said date indicating means, and means responsive to release of said spring for moving said detent out of engagement with said date indicating means.

3. A mechanism according to claim 1 wherein said date indicating means comprises a calendar ring having gear teeth.

4. A mechanism according to claim 3 wherein said teeth are spaced to define slots, said indexing means including a Geneva pinion carrying a pin for reception in one of said slots to drive said calendar ring, said means coupled to said one spring end including a drive wheel having teeth for engagement with the power train of said timepiece, said drive wheel and Geneva pinion being rotatably mounted on a common shaft, said spring comprising a coiled member coupling said drive wheel and Geneva pinion.

5. A mechanism according to claim 4 wherein said locking means includes means for holding said Geneva pinion against rotation, and means operated in synchronism with the hands of said timepiece for temporarily releasing said holding means from said Geneva pinion every twenty-four hours.

6. A mechanism according to claim 5 wherein said detent comprises a rotary circular segment, and pivotal means mounting said segment for movement toward and away from said calendar ring.

7. A mechanism according to claim 1 wherein said means coupled to said one spring end includes a drive wheel adapted to be driven from the power train of said timepiece, said indexing means including a Geneva pinion for indexing said date indicating means, said drive wheel and pinion being mounted for independent rotation, said spring coupling said drive wheel to said Geneva pinion, said locking means including means restraining said Geneva pinion against rotation, and means for periodically freeing said Geneva pinion.

8. An electric watch comprising a calendar ring, a

drive wheel rotated in synchronism with the hands of said watch, a rotatable Geneva pinion, a spring coupling said drive wheel to said Geneva pinion, means coupled to said Geneva pinion and normally spaced from said calendarring for indexing saidv calendar ring, means for restraining said Geneva pinion against rotation, and means operated 'in synchronism with the hands of said watch for temporarily releasing said restraining means at the end of each day.

9. A watch according to claim 8 including a movable detent engaging said calendar ring, and means rotatable with said Geneva pinion for moving said detent away from said calendar ring.

10. A watch according to claim 9 wherein said calendar ring includes spaced portions having a concave surface, and said detent comprises a circular segment rotatable with said Geneva pinion.

No references cited.

RICHARD B. WILKINSON, Primary Examiner.

MICHAEL LORCH, Assistant Examiner. 

1. A CALENDAR MECHANISM FOR TIMEPIECES COMPRISING DATE INDICATING MEANS, A SPRING, MEANS COUPLED TO ONE END OF SAID SPRING FOR CONTINUOUSLY WINDING SAID SPRING FROM THE POWER TRAIN OF SAID TIMEPIECE, INDEXING MEANS COUPLED TO THE OTHER END OF SAID SPRING AND NORMLLLY SPACED FROM SAID DATE INDICATING MEANS FOR PERIODICALLY INDEXING SAID DATE INDICATING MEANS TO THE NEXT DATE, MEANS NORMALLY LOCKING SAID INDEXING MEANS AGAINST MOVEMENT WHEREBY ENERGY IS STORED IN SAID SPRING, AND MEANS OPERATED IN SYNCHRONISM WITH SAID POWER TRAIN FOR PERIODICALLY RELEASING SAID INDEXING MEANS WHEREBY SAID SPRING ACTS THROUGH SAID INDEXING MEANS TO ADVANCE SAID DATE INDICATING MEANS TO THE NEXT DATE. 